Allen Read

Despite being a distinguished etymologist and English professor at New York's Columbia University for nearly three decades, Allen Read, who has died aged 96, was frequently just called "the OK man". Though sometimes tiring of the description, he appreciated the irony of being linked to it, because he was always a stout defender of colloquialisms and slang.

The tag originated in 1941 when Read confounded his fellow scholars by discovering an older origin of the term "OK". He had left his job as a research assistant at the Dictionary of American English, but decided to help out former colleagues trying to pinpoint the origin of the term.

His findings discounted several theories. OK did not stem from "okeh" or "oke", as used by the Choctaw native Americans; nor did it come from the Haitian port of Aux Cayes, the Greek phrase "olla kalla", meaning "all good", or from a tasty US army biscuit made by Orrin-Kendall.

Scrutinising newspapers from the 1840s, which he knew to be the term's birth period, Read discovered that it stood for "Old Kinderhook", a reference to the eighth US president, Martin Van Buren (1837-41), a native of Kinderhook, New York. His supporters had called themselves the Democratic OK Club, asking "Will you not say OK? Go ahead."

Later, Read found an even earlier use of the term. In an 1839 edition of the Boston Morning Post, he came across the phrase "Ok, all correct", from a game of using initials for common expressions. In a fad of the time, these were often deliberately misspelt - for example, the term "no use" was written out as "know yuse", and abbreviated to KY. OK, it transpired, stood for "oll korrect".

In 1963, Read wrote up his findings in a series of academic articles. He also made important contributions to dictionaries, and wrote the entry for the word "dictionary" itself in the Encyclopaedia Britannica. But he was sceptical of such books as arbiters of correct usage - they could, he wrote, become "straitjackets that prevent the swinging, free enjoyment of the mother tongue".

One example against standards that Read liked to quote was the arbitrary naming of the Rocky mountains, which had been known in 1804 as the Northern Andes, and had subsequently been called the Stony, Shining, and even Enchanted mountains.

As well as research papers and monographs, he wrote a number of books, the best known of which was Milestones In The History Of English In America. He loved slang and, in 1928, spent a holiday in the west collecting graffiti in public lavatories. The results were published privately as Lexical Evidence Of Epigraphy In Western North America: A Glossarial Study Of The Low Element In The English Vocabulary. He warned that a preference for the Latinates "defecate, urinate, and having sexual intercourse" was "indicative of grave mental health".

Read was born in Winnebago, Minnesota, got a master's degree from the University of Iowa at the age of 20, and won a Rhodes scholarship to study at Oxford. He taught first at the University of Missouri, and, in 1945, moved to Columbia, from where he retired in 1974.

Since 1938, he had been compiling a dictionary of what he called "Briticisms". Among them were explorations of "old bean", "gent", "bloke", "toff", "cad", "chap" and "lad". His wife of 49 years, the semantics scholar Charlotte Schuchardt, died in July. They had no children. Allen Walker Read, etymologist, born June 1 1906; died October 16 2002